How do I know what browser am I using and which operating system I am using?

From Mozilla Thunderbird go to Tools-> Account Settings-> click Account Action dropdown-> choose Add Mail Account-> at the Mail Account Setup window fill in your email details and click continue-> wait for process to finish should say 'Configuration found by trying common server names'-> below choose the radio button for POP3 (this process is automatic which will aslo set you incoming port to 110 and outgoing to 587)-> click Done and Acceptsecurity to finish